1. Field of the Invention
The present invention relates to a disc device with a disc changer that accommodates a number of optical-disc storage media such as CD or DVD and automatically performs recording or playback of selected one storage medium, especially the disc device being a tray-type disc device with a disc changer having a number of trays that carries the storage media thereon and conveys the media.
2. Related Art
It is necessary in such disc device with the disc changer to accommodate a number of discs and select them for recording and playback, in addition, exchange the selected disc, therefore excessive, many operations including selection, positioning, and conveyance of a sub-tray, selection of a disc, and power switching are necessary, and necessarily additional motors are required as driving sources. On the other hand, a power switching mechanism, in which each operation may be selected and performed smoothly and accurately, is necessary for achieving a structure having a limited number of motors.
For example, “Mechanism for Switching Rotation Transmission” according to JP-A-2002-243015 is configured to perform an ejection operation (operation of conveying to a disc exchange position) of a carriage (sub-tray) and a play operation (operation of conveying to a disc playback position) using a single motor, and switch a driving force channel using a plunger. That is, a configuration is described, in which “a plunger having a lever that moves a rotation gear to a rotation axis direction; a carriage installed in piles such that the ejection operation or the play operation is enabled when either one is selected; a unit for driving the ejection operation and play operation; an motion switching unit for switching motion transmission to a side where either one of the ejection operation and the play operation is selected; and a motion transmission unit for performing the ejection operation or the play operation are provided, and either one of a first gear and a second gear is connected to a motion switching system and the other is connected to a motion transmission system, and a rotation position of the rotation gear is switched so that the rotation gear is detachably fitted to engage with either one of the first gear or the second gear”.
However, in this configuration, noise occurs for each switching by using the plunger, component price becomes high due to the plunger, and power consumption increases, causing heat generation and fire. Moreover, electric wiring and circuit board increase, and the device is necessarily scaled up, therefore there is fear that a magnetic field generated from the plunger has an effect on other components.
“Disc Playback Device with Disc Changer” according to JP-A-10-134474, in which a disc tray transfer operation for disc exchange and a disc tray transfer operation for disc loading are carried out using one motor as a driving source to simplify a mechanism for switching power transmission, is described to have a configuration in which “a first transfer unit that transfers a disc tray horizontally between a disc storage position and a position outside the device, and a second transfer unit that transfers the disc tray between the disc storage position and a playback position are selectively driven by a first driving unit, and a target of power transmission of the first driving unit is determined according to a rotation direction in an initial stage of the first driving unit”.
However, in addition to the conveyance operation of the tray, the motor is required for each of operations of lifting and lowering a traverse unit and driving a pickup, therefore three motors in total are used for the configuration. Thus, the production cost of the disc device with the disc changer increases by just that much, and size is also increased.
In “Disc Player” according to JP-A-2000-105985, a disc player is disclosed, in which a clamp release operation is smoothly performed, and after releasing the clamp, the operation is promptly shifted to a disc conveyance operation. That is, a disc conveyance unit that conveys a disc to the playback position by moving a tray on which the disc is removably mounted, a clamper, a turntable that clamps the disc together with the clamper, a pickup unit, a base that supports the turntable and the pickup unit, and a playback unit including a lifting-and-lowering unit that lifts and lowers the base to move the turntable between a clamping position and an unclamping position are provided; and a protrusion for positioning the tray, which fits into a hole formed in a recess in the tray when the turntable is moved to the clamping position, is provided on the base.
In the device, at the same time when the disc is clamped, positioning of the tray carrying the disc thereon, the pickup unit, and the base moving up and down with supporting the turntable is performed. Accordingly, relative positions among the pickup unit, turntable, and the tray are not displaced during playback, and the clamp release operation after the playback can be smoothly performed without a particular obstacle. Then, at the same time when the clamp release operation of the disc is performed, positioning of the tray is released, and after releasing the clamp, the operation can be promptly shifted to the disc conveyance operation. Thus, operations as the disc player can be promptly performed.
However, when the tray is positioned, temporal delay occurs before the protrusion fits into the hole in the tray located on an upper side of a base member, and the positioning of the tray is performed after the disc is clamped. Therefore, displacement occurs between the disc to be clamped and the turntable. On the contrary, when the clamp is released, since the base member is lowered and the protrusion is disengaged from the hole in the tray and then the clamp is released, in some cases, the disc to be returned is incorrectly carried on the tray.
In this way, the conventional disc device with the disc changer has problems as the above. The invention, which intends to solve issues that are these problems, aims to provide a disc device with a disc changer in which the number of motors is decreased by switching the power channel, and a quiet and stable switching operation without using the plunger is possible, in addition, accurate positioning of the sub-tray and smooth clamp and release of the disc are possible, and the production cost is reduced.